1. Field of the Invention
The present invention is directed to integrated circuit metrology methods and apparatuses, and more particularly to augmentation of projection microscopy methods and apparatuses with optical profilometry methods and apparatuses, and augmentation of optical profilometry methods and apparatuses with projection microscopy methods and apparatuses.
2. Related Art
As the scale of semiconductor devices decreases, control of the profile of the features of integrated circuit structures formed on semiconductor wafers becomes increasingly difficult. Yet to insure high throughput of circuits that perform according to design, it is desirable to obtain the profiles of features of integrated circuit structures, and particularly their critical dimensions.
The profile of structures formed on a wafer can be obtained using projection microscopy, such as critical dimension scanning electron microscopes/microscopy (CD-SEM). In a typical CD-SEM system, images are produced by an electron beam""s transmission through the structures formed on the semiconductor wafer. However, refraction and reflections of the beam from surfaces of the structures can cause distortions in the CD-SEM image.
In one embodiment, a metrology method and system of structures on a wafer includes obtaining a projection image of at least a first portion of the structures on the wafer using a first metrology apparatus. A profile of at least a second portion of the structure on the wafer is obtained using a second metrology apparatus. The information from the profile obtained using the second metrology apparatus and the information from the projection image obtained using the first metrology apparatus are combined using a processor.